Length of docked tail and the incidence of rectal prolapse in lambs1

Abstract

A multistate cooperative study was conducted to study the current issue of tail length in docked lambs and its relationship to incidence of rectal prolapse. A total of 1,227 lambs at six locations were randomly allocated to two or three tail dock treatments: 1) short--tail was removed as close to the body as possible, 2) medium--tail was removed at a location midway between the attachment of the tail to the body and the attachment of the caudal folds to the tail, and 3) long--tail was removed at the attachment of the caudal folds to the tail. Short-docked lambs had a greater (P < 0.05) incidence of rectal prolapse (7.8%) than lambs with a medium (4.0%) or a long (1.8%) dock. Female lambs had a higher (P < 0.05) incidence of rectal prolapse than male lambs. At two stations, lambs were finished either in a feedlot on a high-concentrate diet or on pasture with no grain supplementation. At one station, with a very low incidence of rectal prolapse, there was no difference in incidence between lambs finished in the feedlot or on pasture; however, at the station with a relatively high incidence of rectal prolapse, lambs in the feedlot had a higher (P < 0.05) incidence than lambs on pasture. The half-sib estimate of heritability for the incidence of rectal prolapse was low (0.14). The results of this study strongly implicate short dock length as a cause of rectal prolapse in lambs finished on high-concentrate diets. Furthermore, the results of this study and the only other study known conducted on this issue strongly suggest that docking lambs at the site of the attachment of the caudal folds to the tail will result in a negligible incidence of rectal prolapse.

Vaginal wall weakness in parous ewes: a potential preclinical model of pelvic organ prolapse

“…There was one mild rectal prolapse noted in a ewe with concurrent ovine POP. In a study by Thomas et al, there was a 7.8 % incidence of rectal prolapse in short-tailed lambs (removed as close to the body as possible) [22].…”

Colopexia em ovinos da raça Dorper com prolapso retal

“…Os animais da raça Dorper possuem corte de cauda curta, fator relacionado por THOMAS et al (2003) e BULGIN (2006 como predisponente para a prevalência do prolapso de reto em animais dessa espécie, pois ovinos da raça Santa Inês, criados no mesmo tipo de manejo, não apresentam essa afecção, e são ovinos que não possuem corte de cauda.…”

“…A cauda curta resulta numa maior incidência de prolapso de reto em ovinos, contudo, muitos criadores de ovelhas e produtores de carneiros para exposição realizam a caudectomia completa para criar a ilusão de maior musculatura na região pélvica, não convencidos dos efeitos negativos dessa técnica (THOMAS et al, 2003).…”

“…De acordo com esse autor, a ocorrência de prolapso em animais com cortes de cauda curta se deve ao fato do músculo esfíncter anal se inserir nas primeiras quatro vértebras coccígeas, e quando elas são removidas, os músculos não têm onde se ancorar. THOMAS et al (2003) compararam em experimento realizado em seis localidades nos Estados Unidos, a prevalência de prolapso de reto em ovinos com o tamanho do corte da cauda. Foram realizados cortes de três comprimentos diferentes (curto, médio e longo) e os principais resultados foram que ovinos do sexo feminino tiveram maior incidência de prolapso do que os machos, e que os animais com corte de cauda curto foram os que apresentaram maior incidência desta afecção.…”

Comparative Anatomy of the Ovine and Female Pelvis

“…The coccygeus muscle is palpable through the skin laterally to the tail basis. In tail docked sheep both muscles may undergo anatomical and functional deterioration [20].…”